Method of coating articles



R. A. HlNKLEY ETAL METHOD OF COATING ARTICLES April 24, 1945.

Original Filed May 17, 1939-- 2 Sheets-Sheet 1 April 24, 1945. v RHlNKLEY ET A 2,374,288

METHOD OF COATING ARTICLES Original Filed May 1'7, 1939 2 Sheets-Shea: 2

Patented Apr. 24, 1945 METHOD OF COATING ARTICLES Ray A. Hinkley andJohn Leland Miller, Corning, N. Y., assignors to Corning Glass Works,Corning, N. Y., a corporation of New York Original application May 11,1939, Serial No. 274,290. Divided and this application March 31, 1941,Serial No. 386,188

4 Claims.

s pplication is a division of Hinkley et al.

application Serial Number 274,290, filed May 17,

The present invention relates to the metallizing of glass articles byheating them in known fashion and then spraying the surfaces thereof tobe metallized by presenting such surfaces to a Schoop gun or'other metalspray apparatus. By this method the metal is applied in atomized formand good adhesion to the glass is obtained so long as the glass issufficiently hot and the thickness of the coating is held withinreasonable limits beyond which the coating will tend to spall. Theapplication of a coating to the outer edgesurfaces of a circular articlecan be readily accomplished by simply appropriately spacing it from thenozzle of a Schoop gun and rotating the article while spraying its edgesurface until the desired thickness of co g has been applied. Since insuch an article t e surface thereof beins coated may readily be passedbefore the glin at a constant speed and remains uniformly spacedtherefrom at all times, a uniformly distributed coating is obtainedwithout difliculty. If, on the other hand, the article surface to becoated is of non-circular outline, its surface speed and distance fromthe gun nozzle will vary and an uneven distribution of the coatingmaterial will result.

One object of the present invention is a process by which glass objectseven though of non-circular outline may be given a uniform coating in ahighly efllcient manner.

The present invention embodies among its features facilities for feedingan article to a reheating lehr, transferring the heated articletherefrom to a rotatable support, elevating, seizing,

Y and rotating the article in such a manner as to present a constantlychanging uniform surface area thereof to be coated to a Schoop gunejectms a spray of coating'material, effecting such movement of the gunas to maintain a uniform distance between it and the surface beingcoated, and to thereafter release and pneumatically shown in Fig. 1 andof other apparatus cooperative therewith; and

Fig. 3 is an enlarged plan view of one of the articles to be coated.

The apparatus employed in heating the arti- 'cles to be coated comprisesa circular tunnel lehr ll having a ware support comprising a table l2diagrammaticallyillustrated as being rotatable by a friction wheel l3supported on a shaft ll driven by a variable speed motor l8.

The feeding of an article to the lehr table an the withdrawal of aheated article therefrom is by meansof a rake 20 carried on the free endof a shaft 2| actuated by a piston within a pneumatic cylinder 22. Acontrol valve 25 under the influence of a pair of bleeder valves 26 and21 alternately supplies air to the opposite ends of the cylinder 22 toeffect such actuations.

These bleeder and control valves and others hereinafter referred to areof well known form and are similar to those disclosed in a copendingGoodrich application Serial Number 227,551, filed August 30. 1938. Allcontrol valves are continuously supplied with air from a main supplyline 30 and in turn'. have leakage paths within them which supply air tolines extending to their respective bleeder valves. For example, valve25 receives air via line 30'and a branch line 3| and feeds a part ofthis air out over bleeder valve lines 26' and 21' which are normallyclosed to. atmosphere 'by their bleeder valves 26 and 21. When bleedervalve 25 is actuated, it exhausts line 26' direct toatmosphere causingthe control valve to actuate and supply air to the forward end ofcylinder 22 via an air line 32 and at the same time exhausts therearward end of the cylinder to atmosphere via a line 33, ports I withinthe valve and an exhaust line 34. In a similar fashion the actuation ofbleeder valve 21 causes the valve 25 to operate in such a manner as tosupply air over line 33 to the rearward end of cylinder 22 and toexhaust the forward end thereof to atmosphere. As will readily appearfrom an inspection of Fig. 2, the bleeder valves 26 and 21 with others,hereinafter specifically referred to, are arranged in the desired orderand spaced relation about a timer cam 36 L supported on shaft l1 andhaving a singlelobe for successively actuating the bleeder valves.

The elevating and subsequent lowering of an article is by means of asupport 38 carried by a shaft 40' coupled by a ball bearing assembly 50to a shaft 40, adapted to be raised and lowered by a piston within apneumatic cylinder ll. A control valve 43 under the influence of a pairof bleeder valves 44 and 45 alternately supplies air to the oppositeends of cylinder 4| to effect such ,actuations. The shaft 40 passes;through a sleeve 46 carrying a gear 41 into thehub of which is threadedset screw 48 (Fig. 1) entering a slot 48 in the shaft. This arrangementprovides a drive connection between the shaft 48 and gear 41 whilepermitting sufficient relative endwise movement that when air issupplied to the upper end of cylinder 4| the support 38 is lowered flushwith a stationary platform 5| extending over to the edge of the rotatingtable i2,

from which a heated article is raked onto the support in a mannerhereinafter explained.

The clamping of an article on support 38 during the rotation thereof isby a clamping cup 53 rotatably mounted on an arm 54 supported from ashaft 55 at times under the influence of a shaft 58 actuated by a pistonwithin a pneumatic cylinder 51. A control valve 88 under the influenceof a pair of bleeder valves 8| and 82 alternately supplies air to theopposite ends of cylinder 51 as required to raise and lower its shaft58,

The unloading of an article from support 38 is effected by a bleedervalve 84 which, when actuated, exhausts air from its feed lines 85 and.88 to atmosphere through a line 8'! and an unloading nozzle 88.

The invention is herein applied to the coating of the edge surfaces ofrectangular glass articles 18 having their corners rounded, as clearlyillustrated in Fig. 3. Since it so happens that the surface to be coatedis of substantially rectangular outline, the surface speed variations ofone half thereof, comprising an end and half of each adjoining side ofthe article, will duplicate that of the opposite half of the article.Because of this, the same means can be employed twice during onerevolution of the article to appropriately vary the speed of the articlesupporting shaft 48 in like manner twice during one revolution thereof.Rotation of shaft 48 is by a, motor I2 .through a suitable reductiongearing I3, a friction clutch 14, a gear carried by an associatedvertical shaft I8, a pinion 11, eccentrically mounted gears 18 and 18,and a gear 88 in mesh with the gear 41 on shaft 48'. The foregoing gearsare all one to one ratio excepting gears 88 and 41, which are one to tworatio. It follows, therefore, that for each revolution of shaft 18 shaft48' revolves one-half revolution during which its speed of rotation isvaried in accordance with the eccentricity of gears 18 and 18, and thatone-half of the edgev surface of an article 18 to be coated is rotatedin front of the nozzle of a Schoop gun 8| at a substantially constantperipheral speed. .The other half of the edge surface to be coated is ina similar fashion I advanced in front of the Schoop gun during thesecond revolution of the eccentric gears.

It is essential to stop rotation of the article support when loading andunloading and further to insure its being brought to a stop in properlyoriented rotary position to properly receive the article. lower end ofshaft 48' with a collar 82 (Fig. 1)

carrying dogs 83 extending into a stationary cylrotation of therespective parts is being prevented.

As previously mentioned, the apparatus for introducing articles into thelehr and for withdrawing articles therefrom comprises a rake 28 carriedon the free'end of a shaft 2|, actuated by a. piston within thepneumatic cylinder 22. This rake has a pro'ng 81 which rakes a heatedarticle from the lehr table I 2 onto support 38 at a time that suchsupport is stationary and flush with an associated platform 5|, To keepthe lehr continuously supplied with articles, an attendant at this timeplaces an article on platform 5| in front of a prong 88 of the rake sothat as it returns to the position shown it rakes such article onto therotating table of the lehr.

As soon as an article is oriented on support 38, the lobe of timer cam38 encounters and actuates the bleeder valve under the influence ofwhich control valve 43 is actuated to supply air to the lower end ofcylinder 4| to elevate the support 38 as required to bring the articlecarried thereon into position to receive a deposit from the Schoop gun8|. However, before this height of the platform is attained, theclamp-down cup 53 is encountered. The weight of the supporting arm 54and vertically movable shaft 55 of this cup prevents displacement of thearticle therefrom on subsequent rotation thereof following the raisingof the dogs 83 clear of the slots 88 in cylinder 84.

As previously stated, shaft 55 is at times under the influence of ashaft 58 having a piston operating in a cylinder 51 to which air issupplied by the control valve 88 under the influence of bleeder valves8| and 82. While an article is being coated, bleeder valve 82 isencountered by lobe of cam 38 and causes valve 88 to supply air to thelower end of cylinder 51, thereby bringing the free end of shaft 58 to'such elevation that subsequently as the sprayed article is lowered,consequent to engagement of bleeder valve 45 by the timer cam, andlocked against further rotation, shaft 55 encounters shaft 58 as thesprayed article approaches the horizontal level of nozzle 88.Accordingly, as shaft 45 is lowered slightly farther, the articleisfreed from the clamp 53. Just before this occurs, however, the lobe ofthe timer cam encounters bleeder valve 84 which bleeds air supplied toit by line 88 through line 81 and the nozzle 88. Accordingly, as thesprayed article is lowered to the level of the nozzle it is freed fromcup 53 and blown from support 38 This is accomplished by providing the vuniform distance from the one end and half of rotating, the entire geartrain is held stationary. The slipping of clutch 14, however, permits cotinued operation of the motor I2 during the time onto a suitableconveyor (not shown).

In the period during which the support is flush with platform 5|, inpreparation for the receipt of another article, bleeder valve 6| isactuated and causes the control valve 88 to supply airio the upper endof cylinder 51, thereby positively restoring shaft 58 to its lowermostposition. This enables shaft 55 to lower the clamp member 53 to itsinitial position.

\The distance of the Schoop gun from the surface being coated ismaintained constant by a suitably shaped cam 88 carried by shaft 18 anda return spring 8|. Since the shaft 15 revolves two revolutions to oneof the articles to be coated, the outline of the cam 98 is such thatduring one revolution thereof it effects movement of the gun as requiredto maintain it a substantially each adjoining side of the article edgesurface asraaas constant during passing of the other half of the articleedge surface before the gun.

In order to prevent the upper and lower surfaces of the article beingsprayed from receiving stray particles of the coating material, the gunat is positioned to direct the spray from a level below the top surfaceof the article support 18. With the material striking the edge of thearticle from a level below the plane of the lower surface of the-article,'the tendency to blow the material between the support andarticle is avoided; also,

1 the material ejected above the top surface of the article does notdisfigure it, as such material moves at high velocity and accordinglypasses thereover.

Although the invention has herein been applied to an apparatus forcoating the peripheral edges of a non-circular article of a particularconfiguration, it should be understood that by suitable modification ofthe eccentricity of gears 18 and 19 and of the shapes of cam 80 andsupport 38, such apparatus may be readily adapted to coat the peripheraledges of any other of a wide range of symmetrically shaped articleswithout departing from the spirit and scope of the invention.

What is claimed is:

1. The method of'coating the peripheral surfaces of an article in whichsuch surfaces are different distances from its axial center, whichincludes rotating the article about such center at the varied speedsnecessary to establish a substantially constant peripheral surface speedthereof, directing a spray of coating material toward the peripheralsurface of the article and shifting the root of the spray as necessaryto maintain it a constant distance from the periphery of the article.

2. The method of coating surfaces of an article of non-circular outline,which includes directing a spray of coating material to a minor portionof the surface to be coated, efleoting relative rotation between thearticle and the root of the spray, about an axis passing through thearticle, at varying speeds required to progressively present allsurfaces of the article to be coated to the spray for substantially thesame period of time and at the same time shifting the root of the sprayas required to maintain a substantially uniform space relationshipbetween the article and the root of the spray at all times.

3. The method of applying an non-circular band of coating material to anarticle, which includes directing a spray of coating material against aportion of the article while effecting relative rotary movement betweenthe article and the root of the spray, about an axis passing through thearticle, at varying speeds inversely proportional to the distance of thesurface to be coated from the axis of rotation and shifting the root ofthe spray as required to maintain it in substantially the same positionrelative tothe surface of the article being coated throughout thecoating cycle.

4. The method of applying a non-circular band of coating material to anarticle, which includes directing a spray of coating material against aportion of the article while effecting relative rotary movement betweenthe article and the root of the spray, about an axis passing through thearticle, at varying speeds inversely proportional to the distance of thesurface to be coated from the axis of rotation and shifting the root ofthe spray to maintain the space relationship between the surface beingcoated and the root of the spray substantially constant throughout thecoating cycle.

RAY A. HINKLEY. JOHN LELAND MILLER.

